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Jan
23
revised List of connected Lie subgroups of $\mathrm{SL}(2,\mathbb{C})$.
added 235 characters in body
Jan
23
awarded  Promoter
Jan
23
comment The group $\mathrm{SL}(n,\mathbb{C})$ .
So I have taken a look at Dieudonné's book. I focuses to much on the general case, where $K$ is an unspecified field. The funny thing is he doesn't require the product law to be commutative, which I knew to be an old French specificity, but which I had never seen written. Actually, I am more interested in the Lie group structure, this question echoes the one I asked two days ago : math.stackexchange.com/questions/646183/…
Jan
23
comment The group $\mathrm{SL}(n,\mathbb{C})$ .
I am familiar with the classical results. But I am going to take a look on the book of Dieudonné, thank you very much.
Jan
23
asked The group $\mathrm{SL}(n,\mathbb{C})$ .
Jan
21
comment List of connected Lie subgroups of $\mathrm{SL}(2,\mathbb{C})$.
Of course, I forgot to precise connected.
Jan
21
revised List of connected Lie subgroups of $\mathrm{SL}(2,\mathbb{C})$.
added 10 characters in body
Jan
21
revised List of connected Lie subgroups of $\mathrm{SL}(2,\mathbb{C})$.
added 9 characters in body
Jan
21
comment List of connected Lie subgroups of $\mathrm{SL}(2,\mathbb{C})$.
Sorry I should have precised I am only interested in Lie subgroups of real dimension at least one.
Jan
21
asked List of connected Lie subgroups of $\mathrm{SL}(2,\mathbb{C})$.
Dec
30
asked Difference between diffeomorphisms fixing a point or a whole neighborhood.
Dec
29
accepted Exact sequences and (semi) direct product
Dec
29
comment Exact sequences and (semi) direct product
Thanks. A hint for point 3. ?
Dec
29
asked Exact sequences and (semi) direct product
Dec
25
comment Geodesic flow on a manifold with negative curvature is ergodic
If you are interested in the proof of Mostow rigidity, you can certainly avoid using this result.
Dec
19
revised Linear group action over an hermitian space.
added 453 characters in body
Dec
19
asked Linear group action over an hermitian space.
Dec
14
comment Closed but not exact one-form on $S^2$
Ok I read a bit fast your hypothesis and missed the fact that you removed 3 points. Whatever, I'm not sure I understand what you're asking for in your comment. Could you precise a bit ?
Dec
14
comment Closed but not exact one-form on $S^2$
This cannot happen on $S^2$ because the non-exactness of a closed form must come from a hole on the surface (in rough words). You should try to prove the following : let $S$ be a surface which is simply connected(this express the fact that $S$ has no hole), then every closed $1$-form is exact.
Dec
14
comment Is the matrix defined by $\bar{K}_{ij}=f(x_i)f(x_j)$ for a real valued function $f$ semi-positive-definite?
Other remark, such a matrix will always be of rank at most $1$, since all lines are colinear to $(f(x_1),...f(x_n))$. It implies that it will never be definite positive provided that $n \geq 2$.